Electrically powered artificial lighting for general illumination has become ubiquitous in modern society. Electrical lighting equipment is commonly deployed, for example, in homes, buildings of commercial and other enterprise establishments, as well as in various outdoor settings.
In conventional luminaires, the luminance output can be turned ON/OFF and often can be adjusted up or dimmed down. In some luminaires, e.g., using multiple colors of light emitting diode (LED) type sources, the user may be able to adjust a combined color output of the resulting illumination. The changes in intensity or color characteristic of the illumination may be responsive to manual user inputs or responsive to various sensed conditions in or about the illuminated space.
During emergency conditions, a building (e.g., school or office building) may require evacuation as quickly and safely as possible. When a line power source (e.g., wall power or street power) that powers regular luminaires is interrupted, building codes typically require illumination of the egress pathway using emergency lights. Specific designated egress pathway areas are typically targeted for emergency illumination—stairs, aisles, hallways, ramps, escalators, walkways, and exit passages. Such pathways for egress and exit signage are needed to guide and direct occupants of the building to a public way (e.g., street).
Emergency luminaires continuously emit emergency illumination lighting at an emergency illumination levels, for example at a minimum of 1.0 foot candles (fc) for a 90 minute period. Currently with emergency luminaires, as per Underwriter Laboratories 924 (UL924) standards in the industry for emergency lighting, every emergency light that enters into emergency mode stays for 90 minutes irrespective of recovery of a line power source. The emergency luminaire will remain fully illuminated for at least 90 minutes and normal control restored after a timer set for 90 minutes expires. Because emergency illumination lighting continues to be emitted by the emergency luminaire after line power is restored, electricity is needlessly wasted by the emergency luminaire. Besides power savings, there are other drawbacks to the 90 minute timer approach, fails to detect restoration of line power. In school classrooms where frequent power blips occur due to thunderstorms, teachers are faced with a 90 minute period during which the emergency light fixtures are stuck on at full brightness, which is distracting to the occupants.
Regarding emergency luminaires, U.S. Pat. No. 10,416,243, issued on Sep. 17, 2019, titled “Test Configuration for Emergency Lighting Fixtures,” to applicant ABL IP Holding, LLC, which is incorporated by reference as if fully set forth herein, describes an emergency light fixture and a test configuration. U.S. Patent Publication No. 2019/0252911, published on Feb. 13, 2019, titled “Light Fixture with Power Loss Detection and Emergency Egress Mode,” to applicant ABL IP Holding, LLC, which is incorporated by reference as if fully set forth herein, describes a technique for detecting power loss by a driver in an emergency light fixture and switching the emergency light fixture from a normal operation mode to an emergency mode upon detecting the power loss.
Conventional wall switches and luminaires communicate over wired systems. More recent lighting systems are wireless, which allow communication over a radio frequency (RF) network. Regarding wireless lighting control systems, U.S. Pat. No. 9,820,361, issued on Nov. 14, 2017, titled “Wireless Lighting Control System,” to applicant ABL IP Holding, LLC, which is incorporated by reference as if fully set forth herein, describes a wireless lighting control system that is commissioned over a commissioning network and is controlled over a wireless lighting control network. U.S. Pat. No. 9,883,570, issued on Jan. 30, 2018, titled “Protocol for Lighting Control via a Wireless Network,” to applicant ABL IP Holding, LLC, which is incorporated by reference as if fully set forth herein, describes a wireless lighting control system with lighting control groups.
However, there is no specific network control protocol for emergency luminaires in the wireless lighting control system. Accordingly, efficient network protocols are needed for a wireless lighting control system to allow wirelessly controlled emergency luminaires to efficiently and automatically turn off when line power is restored to overcome these and other limitations in the art.